Headliners for vehicles are conventionally constructed of fiber glass or multi-layered laminated panels incorporating fiber glass and foam resin layers. In the conventional manufacturing process, the layers are placed between mirror image mold surfaces, compressed, heated to cure an incorporated thermosetting resin, and then cut to shape at their periphery. Sometimes apertures for window openings, light fixtures, sun visors and the like are cut in the panels after molding. More often than not, in the assembly of the vehicle the headliner is inserted through the front window before the windshield is mounted. The typical headliner is in the shape of a dome with the concave surface facing downward. It is sufficiently rigid to hold its shape when mounted in the passenger compartment and supported along its side edges with the central part of the headliner juxtaposed to the roof.
Various problems exist in the assembly of the headliner and one of those problems is that the headliner includes a decorative layer as the exposed surface visible to the passengers. Any folds, creases or blemishes in the visible surface creates a problem for one marketing the vehicle. As a practical matter, it is unacceptable to have exposed blemishes. Also, breakage is a problem due to brittleness of the cured structure.
The headliner serves three other functions in addition to aesthetics which may be at odds with the concern for exposed blemishes. One function is to provide a soft surface to minimize injury with head bumps. Fiber glass headliners are hard as are conventional headliners incorporating foamed resin and do not provide much padding for one's head. The only cushioning is in the decorative fabric which may or may not have a soft foam backing. A second function is to provide insulation from heat between the roof of the vehicle and the interior or passenger compartment. The third function is to provide sound insulation from exterior wind noise, engine noise, and the like.
A common solution to the problem of heat and noise insulation is to use foamed resin layers in the headliner. The foamed resin is a better heat and sound barrier than resin impregnated fiber glass. Unfortunately, the foamed resin most often used is of the "closed cell" variety which includes a plurality of bubbles throughout the resin. Such foamed resin is initially quite rigid and with a sealed skin coating it is even more rigid. Therefore, when the headliner must be bent or folded out of its original molded shape to get it into the proper position for installation in the vehicle it often cracks and/or ruptures bubbles within the foamed layer itself. This often leaves a crease in the headliner which is visible through the fabric. That is also true of fiber glass headliners. Exposed creases are a problem because an exposed crease makes the flawed headliner unusable from a practical standpoint. As a consequence of the problem, the size of the windshield opening is often dictated by the size of the headliner which must be inserted (whether the vehicle manufacturer knows it or not). Making the windshield opening larger minimizes deflections of the headliner to get it in operative position.
The problem with fiber glass in headliners, wall panels, etc., is an environmental one. Glass fibers are not recyclable and when a waste or old product is discarded it is not biodegradable and cannot be burned.
Attention is directed to the patent to Romesberg, et al., U.S. Pat. No. 5,468,256. The inventor herein is a co-inventor in that patent and its disclosure is essentially set out in its claim one:
1. A process for making a flexible laminated sheet of foamed resin and fiber comprising,
(a) providing layers of open celled polyurethane foam and non-woven scrim, said foam having a thickness in the ranges of about 0.1 to 1.1 inches, and ILD in the range of 10-80, a density in the range of 0.7-2 pounds per ft.sup.3, and a permeability in the range 2-8 cfm, PA1 (b) providing a layer of material over said scrim layer, PA1 (c) chopping strands of fiber glass to a length in the range 1.5-3 inches and depositing by gravity a first layer of fiber glass over said layer of material, said fiber glass being applied in a density in the range 4-16 gm/ft.sup.2, said layer of material between said first fiber glass layer and said scrim layer confining and supporting said first fiber glass layer. PA1 (d) impregnating said layer of foam with a liquid polyurethane resin, said liquid resin comprising a mixture of about 40-50 volume percent aromatic isocyanate, about 50-60 volume percent polyether polyol, and about 0.0-0.2 volume percent of a catalyst, PA1 (e) running said impregnated foam layer between a first pair of rollers to provide a uniform non-saturating dispersion of said liquid resin in said foam layer, PA1 (f) depositing a second layer of fiber glass over said foam layer, said second fiber glass layer having similar physical characteristics as said first fiber glass layer and being chopped and deposited on said foam layer in the same way as said first fiber glass layer is deposited on said layer of material, PA1 (g) applying said impregnated foam layer and second fiber glass layer over said first fiber glass layer with the foam layer sandwiched between said two fiber glass layers, PA1 (h) compressing all layers together between a pair of calendar rollers to form a laminate with said liquid resin being squeezed from said foam layer into the adjoining fiver glass layers, PA1 (i) applying a cover layer over said second layer of fiber glass, said cover layer being selected from the group consisting of a woven fabric, a permeable vinyl sheet, and an impermeable vinyl sheet, PA1 (j) placing said laminate and cover layer between a pair of molds for a period of about 1/2-3 min. and at a temperature in the range of about 230.degree.-375.degree. F. to form a preform to a desired shape, and PA1 (k) severing the peripheral edges of said preform to a desired configuration.
The use of fiber glass is a problem as indicated above.